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example.com0 points · 0 comments · 11 years ago · Steuard
Extraordinary claims require extraordinary evidence. These drives would violate conservation of momentum.[0] Conservation of momentum is built in to the known laws of physics at an extraordinarily deep level. It is obviously not impossible that our known laws are wrong, but the alternative would be to somehow produce a radically different set of physical laws that nevertheless reproduce every test of existing theory to high precision (as much as 14 digits of accuracy in some cases). And you probably also need to explain why the existing theory worked so very well if its bedrock foundation doesn't describe our universe.
So really, don't get excited. And don't send these folks money that could do real good elsewhere until they give at least some small reason to expect that it's not a wild goose chase.
(Edit to add: I wish this were real, too. With all my heart. But it's not a realistic wish.) [Re-edited to cut some less-appropriate phrasing.]
[0] Yes, I know the EmDrive site FAQ (http://emdrive.com/faq.html) claims that it doesn't violate conservation of momentum. The explanation of why it doesn't actually indicates that it does: "The electromagnetic wave momentum is built up in the resonating cavity, and is transferred to the end walls upon reflection." But the wave's momentum has to come from somewhere, too. So either this is just equivalent to a photon drive (propelled by shooting light out the back), or their device is pulling momentum out of nowhere.
creamyhorror
Tossrock
jdjdps
yohui
And don't send these folks money that could do real good elsewhere until they give at least some small reason to expect that it's not a wild goose chase.
Is it even possible to give them money? I wasn't aware that NASA accepts earmarked donations, or contributions from private individuals in general.
marze
Worth it, even if it has 1 in 10000 odds (my guess).
waterlesscloud
This kind of condescending response doesn't do science or scientists any good. It's actually actively harmful. Don't do it.
DennisP
For some reason, this disturbs a lot of people more than violating conservation of momentum.
The alternative is that there really is absolute velocity, so the basic assumption of relativity is false. But that makes it a pretty big coincidence that atomic bombs work.
Still can't say I mind them checking just to be sure.
madaxe_again
Only hereticks waste their time thinking of such stupid ideas as a heliocentric solar system. They should spend their time productively, and cut up some cats for their humours.
Glyptodon
madaxe_again
Nothing is ever cut and dry, or proved - just commonly accepted and proved within our current paradigm - there's plenty to suggest that we've got the nature of reality fundamentally wrong.
dicroce
http://en.wikipedia.org/wiki/Casimir_effect
I'm not sure this working implies what you think it does.
kowdermeister
Extraordinary claims require extraordinary evidence
So what do you call a second, replicated experimental setup conducted in vacuum, if not extraordinary?
The NASASpaceflight.com group has given consideration to whether the experimental measurements of thrust force were the result of an artifact. Despite considerable effort within the NASASpaceflight.com forum to dismiss the reported thrust as an artifact, the EM Drive results have yet to be falsified.
After consistent reports of thrust measurements from EM Drive experiments in the US, UK, and China – at thrust levels several thousand times in excess of a photon rocket, and now under hard vacuum conditions – the question of where the thrust is coming from deserves serious inquiry.
And also, a quote from the paper he co-authored in mid-2014 (http://ntrs.nasa.gov/search.jsp?R=20140006052):
Test results indicate that the RF resonant cavity thruster design, which is unique as an electric propulsion device, is producing a force that is not attributable to any classical electromagnetic phenomenon and therefore is potentially demonstrating an interaction with the quantum vacuum virtual plasma. Future test plans include independent verification and validation at other test facilities.
i.e. "Something weird and exciting may be going on and let's all verify it and figure it out"
edit 2: io9 has a handy pop-sci summary of the EmDrive: http://io9.com/new-test-suggests-nasas-impossible-em-drive-w...
vvvv edit: Yes, it's very probably a minor phenomenon that's occurring (barring an outright error), and not new physics. But it's a somewhat consistent phenomenon (in separate China & US experiments) associated with this particular test setup, so hopefully we'll learn something of decent interest in the coming years. The skeptical crowd should do its important job and scrutinise the research, and in the meantime, we (and the admittedly enthusiastic Dr White) can hope :)